Do not expose your W's A to her boss, it's not your place to say anything and it's likely they already know, these things don't stay secret for long. Even if everything plays out exactly as you see it in your head and W and OM call it off, where does that leave you? W now hates you even more and is back onto one night stands until she finds OM3.
It sounds like W and OM1 is a rocky relationship so I'm not sure why you are so concerned they are going to ride off into the sunset and live happily ever after. Just let it die naturally and spend your time now becoming the man only a fool would leave.
I can't imagine being treated the way your W is treating you now, I'm so sorry. Best just to give her time and space, she will come around.
Me 28 W 27 T 10 M 2 No kids (fertility issues - mine) Bomb 7/20/2014 - EA Confirmed W moved out 9/15/14 W dating OM 11/22/14